Problem: $ { \left[\begin{array}{rr}{-2} & {-2} \\ {1} & {2}\end{array}\right]-\left[\begin{array}{rr}{1} & {1} \\ {2} & {3}\end{array}\right] = {?} } $
Answer: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{-2}-{1} & {-2}-{1} \\ {1}-{2} & {2}-{3}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-3} & {-3} \\ {-1} & {-1}\end{array}\right]}$